Field of the Invention
Embodiments of the disclosure relate to the field of display technique, in particular to a method and a device for attaching a backing film to a flexible substrate and a roller.
Description of the Related Art
With the development of the display technique, more and more electronic devices employ flexible substrates which are light, thin and have good impact resistance. A display device utilizing the flexible substrate includes a liquid crystal display device, an organic electroluminescence display device and an electrophoretic display device. A flexible display device may be applied to a smart card, a portable computer and an electrical paper. Currently, the process for manufacturing flexible displays has developed greatly. In general, the flexible substrate is firstly fixed on a glass substrate, and then backing plate preparing process is performed. This process is compatible with the preparing process of the existing liquid crystal display device. After the preparing is completed, it is necessary to separate the flexible substrate from the glass substrate and then attach a film sheet (a backing film) to a back surface of the flexible substrate so as to make the flexible substrate flat. Thereafter, processes such as a cutting process, a flexible circuit board bonding process.
Typically, the backing film is attached to the flexible substrate by means of a roller, i.e., exerting a pressing force to the flexible substrate placed on an upper worktable and the backing film placed on a lower worktable by a roller to attach them with each other. In such an attaching device, a roller is encapsulated on an external surface thereof with roller encapsulating rubber made of organic material with elasticity. During the attaching, due to the action of the exerted pressure, the roller is deformed when being subjected to stress, which results in too great deformation at both sides of the roller encapsulating rubber, thereby generating accumulation so that the pressure is too large. Further, both the flexible substrate and the backing film are made of organic material, thus they will also be deformed when being subjected to pressing force. Therefore, when both sides of the roller encapsulating rubber are deformed greatly, the resultant excessive pressure will cause irreversible deformation of the flexible substrate and the backing film, which may cause the flexible substrate after the attaching process varies in size due to large pressure variation. Further, the subsequent bonding process of the flexible substrate to the flexible circuit board is sensitive to variation of the flexible substrate in size. Therefore, the variation of the flexible substrate in size will result in problems such as misplacement of a terminal on the substrate with a terminal of the flexible circuit board, circuit failure when bonding, thereby severely influencing product yield. For high generation production line, the size of the substrate increases, and the size of the roller will increases accordingly, the above problem is more severe.
Therefore, a technical problem to be solved in the art is how to improve uniformity of exerting force when attaching the backing film to the flexible substrate so as to improve uniformity of the size of the flexible substrate after attaching the backing film.